500v Insulation Resistance Test ok?

[shinypen]

Hi all, still training so please forgive my very simple question. Why is it ok to test an appliance at 500vdc when PAT testing but great care should be taken to remove all equipment when IR verifying a new circuit installation?

Is it simply just because connected equipment will make a nonsense of the IR test for a new circuit and not because the voltage will damage e.g a TV?

Many thanks. Rob.

 

[westward10]

A 500v test is, as you say no different to a PAT. I do loads of Periodics and rarely disconnect anything unless connected equipment is causing a fault.

 

[shinypen]

Thanks!

 

[telectrix]

with PAT testers, the meter shorts L and N and tests @500v to E. this way the 500V does not get applied across L and N, which could damage some equopment.

 

[shinypen]

Oh ok, great. Was aware of this for IR testing in general so thanks.